This application claims priority to prior applications JP 2002-014032, JP 2002-015391, and JP 2002-015393, the disclosures of which are incorporated herein by reference.
This invention relates to an air conditioner for a vehicle and particular to an air conditioner comprising a hybrid compressor which is adapted to obtain drive force from a prime mover, i.e., an engine mounted on the vehicle and from an electric motor different from the prime mover.
There is known an air conditioner mounted on a vehicle, i.e., an automobile. Such an automobile air conditioner includes a refrigerating or refrigerant cycle. The refrigerating cycle comprises a compressor connected as one of components thereof. The compressor may be of a type driven by an automobile engine or a type driven by a special electric motor mounted on an automobile.
Japanese Unexamined Utility Model Publication No. H6-87678 (JP 6-87678 U) discloses an automotive air conditioner using a compressor which can be driven by one of an automobile engine and an electric motor, i.e., a hybrid compressor. In the automotive air conditioner, the compressor is driven by the automobile engine when the automobile engine is operated. When the automobile engine is stopped, the compressor is driven by the electric motor.
However, in case where the compressor is driven by the automobile engine, a driving speed of the compressor depends upon the rotation speed of the engine. If an air-conditioning load is great, an air-conditioning ability may sometimes be insufficient. On the other hand, if the compressor is driven by the electric motor, the rotation speed of the compressor is restricted if the capacity of an electric power source of the automobile is insufficient. In this case also, if the air-conditioning load is great, the air-conditioning ability may sometimes be insufficient. The above-mentioned disadvantages result from the fact that the compressor is driven only by a selected one of the automobile engine and the electric motor.
It is therefore an object of the present invention to provide an air conditioner for a vehicle, using a hybrid compressor and capable of achieving an excellent air-conditioning ability.
It is another object of the present invention to provide an air conditioner of the type described, which is improved in performance by appropriately controlling operation of a hybrid compressor.
It is still another object of the present invention to provide an air conditioner of the type described, which allows reduction in power consumption of a hybrid compressor during high-speed rotation of a prime mover as well as decrease in torque shock known in the art.
It is yet another object of the present invention to provide an air conditioner of the type described, which is capable of minimizing variation in air-conditioning ability even if the rotation speed of a prime mover for driving a hybrid compressor is varied.
It is a further object of the present invention to provide an air conditioner of the type described, in which an electric motor for driving a hybrid compressor can be optimally controlled even if an electric power is restricted.
It is a still further object of the present invention to provide an air conditioner of the type described, which is capable of minimizing variation in air-conditioning ability when a hybrid compressor is driven simultaneously by both of a prime mover and an electric motor.
Other objects of the present invention will be clear as the description proceeds.
According to an aspect of the present invention, there is provided an air conditioner for a vehicle, comprising a hybrid compressor which includes a first compression mechanism driven by a first drive source, a second compression mechanism driven by a second drive source, and a single discharge port connected to the first and the second compression mechanisms, a refrigerating cycle connected to the hybrid compressor, and a controller connected to the hybrid compressor for controlling an operation of the hybrid compressor in accordance with a control mode, the controller includes an operation mode setting portion for setting a first operation mode in which the first compression mechanism alone is driven, a second operation mode in which the second compression mechanism alone is driven, a third operation mode in which the first and the second compression mechanisms are simultaneously driven, and a fourth operation mode in which the first and the second compression mechanisms are simultaneously stopped, and a mode selecting portion connected to the operation mode setting portion for selecting, as the control mode, one of the first, the second, the third, and the fourth operation modes.